1,973 research outputs found

    Evaluating the Barrier Effect of a Major Highway on Movement and Gene Flow of the Northern Flying Squirrel

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    Roads are pervasive sources of habitat fragmentation around the world, affecting an estimated 19 percent of the land area of the coterminous United States (Forman 2000). The barrier effect of roads has been demonstrated for species from multiple taxa. Still, information DNA was extracted from cheek cells of 41 individuals and genotyped at 12 microsatellite loci to characterize patterns of population structure. Seven of 16 monitored squirrels crossed the highway at least once during their nightly movements. Randomization tests of the movement data do not indicate significant avoidance of crossing the highway corridor. Movement does not necessarily equate to gene flow, however, and forthcoming analysis of microsatellite data will help elucidate whether current rates of movement are sufficient to maintain genetic connectivity across the highway. regarding the response of the vast majority of species to roads is lacking. We examine the effects of a major roadway on the movement and population genetics of Northern flying squirrels (Glaucomys sabrinus) in the Cascade Mountains of Washington, USA. During 2009 and 2010, flying squirrels (n = 16) were trapped and radio-tracked to gather data on movement within their home ranges and to detect movement across the roadway. Additionally

    Observing the Effects of Inbreeding and Local Adaptation on Fitness in Westslope Cutthroat Trout Populations in a Common Garden

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    Montana Westslope cutthroat trout (Oncorhynchus clarkii lewisi, WCT) populations, particularly those east of the continental divide, are predominantly small and isolated from one other. Small population size inevitably leads to a more inbred population and can lead to lowered fitness (inbreeding depression). Isolated populations may experience local adaptation, which increases the fitness of a population within its native habitat. If inbreeding is the greatest threat to a population, introducing individuals from another population might be the best management decision. However, if local adaptation has also occurred, introducing new individuals might lower the fitness of the population. Our goal was to evaluate the relative importance of inbreeding and local adaptation on fitness in several WCT populations. This study combines eggs from several populations of WCT into several different natural habitats. Remote-site incubators were used to introduce eggs to six sites over four years in the Cherry Creek drainage. Each year a colder and warmer site was selected to test for the potential of local adaptation to stream temperature. Electrofishing was used to sample above and below introduction sites one, two, and three years after eggs were introduced. DNA sequencing of microsatellite loci in parents and offspring were then used to determine the population of origin of 511 offspring sampled in Cherry Creek in 2008 and will ultimately be used for over 750 offspring sampled in 2007 and 2009. Preliminary results suggest that a colder common habitat produces larger differences in relative fitness than a warmer habitat

    Genetic Population Structure of Mule Deer Odocoileus Hemionus Across Montana

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    We conducted a genetic assessment of mule deer (Odocoileus hemionus) population structure across Montana in an effort to understand dispersal routes across the landscape. To assess genetic structure we genotyped 14 microsatellite loci in 359 individuals sampled primarily within Montana. Smaller samples were included from Wyoming, Colorado and Utah in order to provide a regional context for the levels of population structure observed within Montana. Additionally, we sequenced the control region of the mitochondrial genome of 76 individuals subsampled from our original samples across Montana. To avoid potential influences of a priori population designations, individual based analyses were used to test relatedness across the landscape. Weak isolation by distance characterized mule deer individuals across this region. In addition, we did not detect any evidence of spatial autocorrelation in discrete distance classes as small as 10 km. Female mule deer had higher average individual pairwise genetic distances than males, indicating the presence of a contemporary male bias in dispersal rates. Mitochondrial DNA indicated the potential for either reduced overall or female-specific dispersal between a subset of the sampling regions within Montana. Finally, we were unable to detect a genetic signature of past translocations of mule deer across Montana. Taken together these results indicate that within this landscape mule deer populations are characterized by high levels of connectivity and experience few, if any, barriers to dispersal

    Performance of Westslope Cutthroat Trout Released into the Upper Cherry Creek Drainage Using Remote Stream Incubators

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    A major effort to conserve westslope cutthroat (Oncorhynchus clarkii lewisi; WCT) is underway throughout Montana. One of the larger WCT conservation projects is onging in the Cherry Creek drainage of the Madison River. About 105 km of stream and a mountain lake are being treated with piscicides to remove nonnative trout, and WCT are being introduced into the drainage using remote stream incubators (RSIs). We are evaluating the relative success of different wild and hatchery stocks of WCT released into Cherry Creek. Here, we report on survival, abundance, growth, condition, and dispersal of WCT in the upper Cherry Creek drainage during the first three years of releases. Two streams of similar size, upper Cherry Creek and Cherry Lake Creek, meet to form main Cherry Creek. Cherry Lake Creek is colder than upper Cherry Creek (average August temperature about 3?C colder).Known numbers of WCT embryos were placed into RSIs at two sites in upper Cherry Creek during 2006 and 2007, one site in Cherry Lake Creek during 2006 and 2007, one site in Pika Creek (a tributary to Cherry Lake Creek) during 2008, and in an un-named spring-fed tributary to main Cherry Creek just below the mouth of Cherry Lake Creek during 2008. Fry that hatched in each RSI were captured and counted prior to release. Population abundances were estimated by single and multiple-pass electrofishing in 100-m sample sections located systematically throughout the upper reaches of the drainage. Estimated survivals from egg to fry, fry to age- 1, age-1 to age-2, and age-2 to age-3 ranged from 13 to 80 percent, 7 to 80 percent, 21 to 100 percent, and 100 percent, respectively. Survivals in the colder stream, Cherry Lake Creek, were lower than in the warmer stream. Over 3500 WCT occupied the upper Cherry Creek drainage by 2009. Fish dispersed short distances upstream and long distances downstream, but downstream dispersal appeared relatively discrete, with WCT filling available habitat near RSIs before occupying reaches further downstream. Early growth of WCT was much slower in colder streams, but by age-3 little difference existed among streams. Conversely, condition factors of WCT were slightly lower in upper Cherry Creek (averaging 0.88 to 0.95) than in Cherry Lake Creek (0.92 to 1.11). The introduction of WCT in upper Cherry Creek has been successful to date; however, natural reproduction by introduced WCT has not yet occurred, but is expected to occur next year

    Thermal Adaptation of Westslope Cutthroat Trout

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    Populations of westslope cutthroat trout (Oncorhynchus clarkii lewisi), a State species of special concern, have declined throughout their native range. Genetic introgressions, mainly from rainbow trout (O. mykiss), but also from Yellowstone cutthroat trout (O. c. bouvieri), and habitat loss are believed to be the leading causes of this decline. Populations that remain are often small and isolated, thereby increasing their risk of inbreeding depression and extinction. Translocation projects may offer a solution by infusing new genetic material into populations and potentially increasing their probability of persistence. However, local adaptations must be considered when selecting a donor population. We investigated thermal adaptations of four wild populations of westslope cutthroat trout from the Missouri River drainage and one hatchery population from the Washoe Park Trout Hatchery, Anaconda, Montana. Two wild populations were deemed to be from warm streams and two from cold streams. Fish were spawned streamside and at the hatchery. The resulting embryos were placed in experimental systems at 8, 10, and 14 °C. Survival was monitored throughout incubation. Post-embryonic growth was measured 90 days after hatching. Relationships between population performance and natal stream thermal characteristics were examined for adaptive differences

    Estimating Grizzly and Black Bear Population Abundance and Trend in Banff National Park Using Noninvasive Genetic Sampling

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    We evaluated the potential of two noninvasive genetic sampling methods, hair traps and bear rub surveys, to estimate population abundance and trend of grizzly (Ursus arctos) and black bear (U. americanus) populations in Banff National Park, Alberta, Canada. Using Huggins closed population mark-recapture models, we obtained the first precise abundance estimates for grizzly bears ( = 73.5, 95% CI = 64–94 in 2006;  = 50.4, 95% CI = 49–59 in 2008) and black bears ( = 62.6, 95% CI = 51–89 in 2006;  = 81.8, 95% CI = 72–102 in 2008) in the Bow Valley. Hair traps had high detection rates for female grizzlies, and male and female black bears, but extremely low detection rates for male grizzlies. Conversely, bear rubs had high detection rates for male and female grizzlies, but low rates for black bears. We estimated realized population growth rates, lambda, for grizzly bear males ( = 0.93, 95% CI = 0.74–1.17) and females ( = 0.90, 95% CI = 0.67–1.20) using Pradel open population models with three years of bear rub data. Lambda estimates are supported by abundance estimates from combined hair trap/bear rub closed population models and are consistent with a system that is likely driven by high levels of human-caused mortality. Our results suggest that bear rub surveys would provide an efficient and powerful means to inventory and monitor grizzly bear populations in the Central Canadian Rocky Mountains

    The Imaging X-ray Polarimetry Explorer (IXPE): Technical Overview

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    The Imaging X-ray Polarimetry Explorer (IXPE) will expand the information space for study of cosmic sources, by adding linear polarization to the properties (time, energy, and position) observed in x-ray astronomy. Selected in 2017 January as a NASA Astrophysics Small Explorer (SMEX) mission, IXPE will be launched into an equatorial orbit in 2021. The IXPE mission will provide scientifically meaningful measurements of the x-ray polarization of a few dozen sources in the 2-8 keV band, including polarization maps of several x-ray-bright extended sources and phase-resolved polarimetry of many bright pulsating x-ray sources

    Search for exotic resonances decaying into WZ/ZZ in pp collisions at √s=7 TeV

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    Journal of High Energy Physics 2013.2 (2013): 036 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMA search for new exotic particles decaying to the VZ final state is performed, where V is either a W or a Z boson decaying into two overlapping jets and the Z decays into a pair of electrons, muons or neutrinos. The analysis uses a data sample of pp collisions corresponding to an integrated luminosity of 5 fb-1 collected by the CMS experiment at the LHC at √s=7 TeV in 2011. No significant excess is observed in the mass distribution of the VZ candidates compared with the background expectation from standard model processes. Model-dependent upper limits at the 95% confidence level are set on the product of the cross section times the branching fraction of hypothetical particles decaying to the VZ final state as a function of mass. Sequential standard model W′ bosons with masses between 700 and 940 GeV are excluded. In the Randall-Sundrum model for graviton resonances with a coupling parameter of 0.05, masses between 750 and 880 GeV are also exclude

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good
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